The Flow Cytometry Core, under the supervision of Dr. Engleman, will support all four of the projects by providing cell sorting and immunofluorescence analysis services. Equipment available to this core, which is located at the Stanford Blood Center, include a FACS Vantage flow cytometer capable of four color fluorescence analysis as well as automated cell sorting, a Coulter Epics II analyzer, and a Baker 9000 cell counter. Extensive utilization of this core is anticipated, since identification, isolation and phenotype analysis of leukocyte subpopulations are required for the projects being served.